NAME

       nbdkit - A toolkit for creating NBD servers

SYNOPSIS

        nbdkit [-f] [-g GROUP] [-i IPADDR] [-P PIDFILE] [-p PORT]
               [-r] [-s] [-U SOCKET] [-u USER] [-v] [-V]
               PLUGIN.so [key=value [key=value [...]]]

DESCRIPTION

       "nbdkit" is both a toolkit for creating Network Block Device (NBD) servers from "unconventional" sources
       and the name of an NBD server.

       To create a new block device source, all you have to do is write a few glue functions.  The liberal
       licensing of nbdkit is meant to allow you to link nbdkit with proprietary libraries or include nbdkit in
       proprietary code.

       If you want to write an nbdkit plugin, you should read nbdkit-plugin(3).

       Several plugins may be found in "LIBDIR/nbdkit/plugins" where "LIBDIR" is set at compile time and might
       be a path such as "/usr/lib", "/usr/lib64" or "/usr/local/lib".

EXAMPLES

       Serve file "disk.img" on port 10809:

        nbdkit .../plugins/nbdkit-file-plugin.so file=disk.img

       Run the example1 plugin and connect to it using guestfish(1):

        nbdkit .../plugins/nbdkit-example1-plugin.so
        guestfish --ro -a nbd://localhost

       Run the example3 plugin and connect to it using guestfish(1):

        nbdkit .../plugins/nbdkit-example3-plugin.so size=1G
        guestfish --ro -a nbd://localhost

       To display usage information about a specific plugin:

        nbdkit --help .../plugins/nbdkit-example1-plugin.so

GLOBAL OPTIONS

       --help
           Display brief command line usage information and exit.

       -f
       --foreground
       --no-fork
           Don't fork into the background.

       -g GROUP
       --group GROUP
           Change group to "GROUP" after starting up.  A group name or numeric group ID can be used.

           The server needs sufficient permissions to be able to do this.  Normally this would mean starting the
           server up as root.

           See also -u.

       -i IPADDR
       --ip-addr IPADDR
       --ipaddr IPADDR
           Listen on the specified interface.  The default is to listen on all interfaces.  See also -p.

       -P PIDFILE
       --pid-file PIDFILE
       --pidfile PIDFILE
           Write "PIDFILE" (containing the process ID of the server) after nbdkit becomes ready to accept
           connections.

           If the file already exists, it is overwritten.  nbdkit does not delete the file when it exits.

       -p PORT
       --port PORT
           Change the TCP/IP port number on which nbdkit serves requests.  The default is 10809.  See also -i.

       -r
       --read-only
       --readonly
           The export will be read-only.  If a client writes, then it will get an error.

           Note that some plugins inherently don't support writes.  With those plugins the -r option is added
           implicitly.

           Copy-on-write (or "snapshot") functionality is not supported by this server.  However if you are
           using qemu as a client (or indirectly via libguestfs) then it supports snapshots.

       -s
       --single
       --stdin
           Don't fork.  Handle a single NBD connection on stdin/stdout.  After stdin closes, the server exits.

           You can use this option to run nbdkit from inetd, systemd or similar superservers; or just for
           testing; or if you want to run nbdkit in a non-conventional way.

           This option implies --foreground.

       -U SOCKET
       --unix SOCKET
           Accept connections on the Unix domain socket "SOCKET" (which is a path).

           nbdkit neither creates nor deletes this socket.  You should create the socket and set the desired
           permissions and ownership before running the server.

       -u USER
       --user USER
           Change user to "USER" after starting up.  A user name or numeric user ID can be used.

           The server needs sufficient permissions to be able to do this.  Normally this would mean starting the
           server up as root.

           See also -g.

       -v
       --verbose
           Enable verbose messages.

           It's a good idea to use -f as well so the process does not fork into the background (but not
           required).

       -V
       --version
           Print the version number of nbdkit and exit.

PLUGIN CONFIGURATION

       After specifying the plugin name you can (optionally, it depends on the plugin) give plugin configuration
       on the command line in the form of "key=value".  For example:

        nbdkit .../plugins/nbdkit-file-plugin.so file=disk.img

       To list all the options supported by a plugin, do:

        nbdkit --help .../plugins/nbdkit-file-plugin.so

SEE ALSO

       nbdkit-plugin(3), nbdkit-example1-plugin(1), nbdkit-example2-plugin(1), nbdkit-example3-plugin(1),
       nbdkit-file-plugin(1), nbdkit-gzip-plugin(1), nbdkit-libvirt-plugin(1), nbdkit-vddk-plugin(1).
       nbdkit-xz-plugin(1).

AUTHORS

       Richard W.M. Jones

COPYRIGHT

       Copyright (C) 2013 Red Hat Inc.

LICENSE

       Redistribution and use in source and binary forms, with or without modification, are permitted provided
       that the following conditions are met:

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           the following disclaimer.

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           the following disclaimer in the documentation and/or other materials provided with the distribution.

       •   Neither the name of Red Hat nor the names of its contributors may be used to endorse or promote
           products derived from this software without specific prior written permission.

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